Stand-alone interbody cage versus anterior cervical plate for treatment of cervical disc herniation: sequential changes in cage subsidence.

Anterior cervical discectomy and fusion with an autogenous iliac bone graft is the gold standard treatment for cervical disc herniation. However, autologous bone grafts obtained from the anterior iliac crest are associated with significant donor-site morbidity and complications. To decrease bone graft-related problems, several types of interbody fusion cage have been developed and are used widely in clinical practice. We compared the clinical and radiological outcomes for two surgical procedures used to treat cervical disc herniation: the stand-alone interbody cage and autologous iliac bone grafting with an anterior plate. The clinical results did not differ between patients treated with the two procedures. The stand-alone cage was less invasive and had less donor-site morbidity. In patients treated with the bone graft and plate, the alignment of the fused segment was maintained in all but one patient, who exhibited nonunion. In contrast, in the cage-treated group, 44% of patients exhibited loss of lordotic alignment of more than 5 degrees and cage subsidence of 3 mm or more. All cage subsidence occurred within 3 months of surgery. Although the stand-alone cage was a less invasive and more effective procedure to treat cervical disc herniation, surgeons should consider the possible drawbacks of the associated subsidence.